Seam protecting devices for cloth shears



Jan-15, 1946. w HADLEY 2,393,159

SEAM PROTECTING DEVICES FOR CLOTH SHEARS Filed Dec. 8, 1943 3 SheetsSheet 1 Jan. 15', 1946. w. N. HADLEY 2,393,159

SEAM PROTECTING DEVICES FOR CLOTH SHEARS Filed Dec. 8, 1943 3 Sheets-Sheet 2 Jan. 15, 1946. w D 2,393,159

SEAM PROTECTING DEVICES FOR CLOTH SHEARS Filed Dec. 8, 1945 s Sheets-Sheet s VII/I i maml l nl lll; l

14 14/050 /V. HADLEY.

- E gy- ('6 .{A W 5 Patented Jan. 15, 1946 UNITED STATES PATENT OFFICE SEAM PROTECTING DEVICES FOR CLOTH SHEARS Wilfred N. Hadley, Springfield, Vt., assignor to Parks and Woolson Machine Company, Springfield, Vt., a corporation Application December 8, 1943, Serial No. 513,435

20 Claims.

This invention relates to cloth shearing machines utilizing rotary shear blades 'coacting with stationary ledger blades to shear the protruding fibers at the surface of the cloth to a uniform level of extent, the cloth being run rapidly through the machine and past these coacting blades in open and fiat relation, being supported in close proximity to the blades usually by means of a rest solidly supporting the cloth at the shearing point or. closely adjacent thereto. The spacing betweenthis rest and the shearing blades is customarily so close that the increase in thickness of the traveling web caused by the seams joining successive pieces or cuts of cloth will result in cutting and damaging the cloth or injuring the shearing blade if allowed to enter this narrow space. To prevent this injury manual or automatic means are provided to suspend the shearing of the cloth during the passage of the seam, either by increasing this spacing, as by lifting the blades or. drop ping the rest, or by stopping or reversing the rotational. the rotary shearing blade. When the means for thus passing the seam without cutting it are automatic in their action, they are controlled and actuated by feelers or other detecting devices detecting and responding to the approach of the seam to the shearing point.

' The present invention has particular relation to this-latter class of automatic seam-protecting mechanisms and has among its objects the provision of novel and improved devices of this sort which shall be easier to set for various clothspeeds and more accurate in their operation, whereby the chance of accidental cutting of the seam is eliminated or greatly reduced, and the length of unshorn cloth adjacent the seam is diminished, the proportion of finished and salable fabric in each piece being thus increased with obvious saving to the manufacturer.

To these ends, the invention comprises an automatic seam-protecting mechanism for either solid-:rest or gap-rest single and multiple cloth shears having detector devices detecting the approach of a seam to the shearing point, means receiving'and holding the impulse from the detecting devices for whatever length 'of time is necessary until the seam arrives within an inch or so of the shearing point, shearing-suspending devices which are thereupon actuated by an impulse from the said means to stop the shearing while the seam passes the shearing point, and additional means adjustable to suit the cloths speed effecting a resumption of the shearing operation after the seam has passed the shearing point by an inch or so. In its preferred embodiment,

the invention provides time delay devices easily and accurately set to provide any desired delay between the detection of the approach of a seam and its arrival at the shearing point, thus allowing the cloth to be run at widely differing speeds as required by different fabrics, and also enabling the duration of the suspension and the length of the unshorn area which includes the seam, and

for automatically extending the period of suspension in case a seam reaches the shearing point in diagonal, bowed, or crooked relation. It further provides means for automatically making these necessary adjustments of the time delay between detection of the approach of the seam and the suspension of the shearing, and of the period between suspension and resumption, in the act of manipulation of the controls which govern the change in the cloth speed.

These provisions, as well as other aims of the invention, and-the manner of their attainment, are as set forth hereinafter.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which- Fig. 1 is a diagrammatic end elevation of one section of a'multiple blade cloth shear, showing only the parts immediately concerned with the invention, and illustrating the seam-detecting and shearing-suspending mechanism.

Fig. 2 is a wiring diagram of the automatic controls intervening between the seam-detecting devices and the shearing-suspending devices of Fig. 1, and governing the actuation of the latter devices, and also showing in simplified diagrammatic manner the connections to the detecting and shearing-suspending devices of the several blades of amultiple shear having three blades or shearing sections, such as shown in Fig. 1.

Fig.3 is a side elevation of the Variable speed drive for the cloth in the multiple shear of Figs. 1 and 2, showing the means for automatically varying the periods of delay and the times of suspension and resumption of shearing to match the changes in cloth speed.

'Fig. 4 is an end elevation of the same, viewed from the right-hand end.

Fig. 5 is a detail of parts of Fig. 4.

The invention is shown embodied in connection with a three-blade Parks & Woolson multiple sheaf, of which the three shearing sections are indicated diagramatlcally at A, B and C respectively in connection with the wiring diagram in Fig. 2. A more detailed but still diagrammatic showing of a single shearing section of the three in Fig. 2, herein the first section A, is presented in Fig. l, in which the cloth 50 travels in the di- 'rection of the arrows around various guide-rolls 52 and fe'e'd r'ol-Is 154, past the raisihg brushjli and clearer brush 58 andover the sharp top edge of the cloth-rest 60, where the protruding fibers are sheared by the coaction of the usual con tinuou'sly revolving spiral-bladed knife 62 and the ledger blade 64, both of which'ar mouht'ed on carriage including brackets 66 which swings about frame "and having it's 'fre h s pivotauy cbnnected to a lil'lk 86 {iii/Dfi'dlb the 2/ @fuifi? 6f $016- n-cid magnet 90. When thsolehoitl is actuated t'b 'dfaw do'w'n' i't's armat re tne blade carnag is rccked cibckwis an the braces are retracted from the (3101311 to 'Sus'p'hd the sheifiillg While the seam is passing 'thesuensg 'rc detect the approach 'df the seam to the sneanng paint, any suitable detecting devices en ui e ercer or these set rei'tng n Pa'tntsNo's. 2,321,431 and 2,321,482 and 2,375,732 provided, infth intereste fnbodfineht comprising a 13111- rali ty of spring fe'le r 92 having their ups bhtrat asharpan'gie and iesinentiy pressing aaihst the cloth sq where the latter travels name "a institute-"seemed pistes 'ioll '94 r venih'g freely in bearings in fram 12, the feeler wires 92 recurring atinte'rvalsbf an inch or less either continuously b'rin spaced groups across the width of the cloth and thus forn ling a comb-like structure. Apertures are purpb'sely formed the web of cloth at ar a predetermined relation to the seams 9'6, wherebyfthetips of one or more of the feeler wires make electrical contact withthe surface of platen roll 94 to complete an electrical ,ci'rci it and fthu'st'o start an impulse eventually results in the energizing of solenoid 99 to lift the blades and suspend the shear- 15g long enough to let the seam 96 pass the blades. V M

The feeler wires are mounted electrical connection with a bar 98 m'ounted in insulating brackets B8 on the machine-frame, this bar being connected by a wire or lead topost-Apn terminal board l b-l, Fig. 2, While the platen roll 94 is connectedby a wire to post l l on board IIH. Likewise, the leads by which solenoid 90 is'energized are brought to posts l5 and ;,l6 respectively on the board 1-91. Similarlwin-theseoond and third shearing unit Band C of the-three-bladeshear, the leads from the feeler comb respectively run to posts B andC on board-.101, while the corresponding platen rolls are connected to the common return wire attached to post -H ont-he board;

the leads from the solenoids of unitsB and Care brought out to posts l-l, 18,;and 19,- -20, respectively, on board I01. A, h

The main current supply, herein 440 volts, is brought to posts 1 and fl on'board 101 bysuitable Ina-ins from asource of'ralternating -,cu'rrenti6?l, whence it is carried by leads -1;8, tothe terminals .Windings of the solenoid 90 to effect the actual lifting of the knives.

When contact is made between feeler-comb 92 and slates roll '9 of the first section A of the shear, by way or the apertures purposely formed in or adjacent the seam, 12-volt current flowing via lead H to post H and thence via the continuation of lead I I, forming the common return wire, through the platen roll and feeler-eomb to post A travels through lead l2 to a relay RI, through the coil thereof, and back via lead 21 toTZ. This energizes the coil of RI momentarily, drawing dbwn the contact makers 'of such relay to supply llO-volt current ;from '-Il v-ia'leads l4 and 22 to the coil of-relay; R4-, the circuit being completed via lead 23 to Tl. moves the armature of Rttocause all four of -its contact makers to complete their contacts. The closing of a branch of lead z to lead 25 by one of these contacts holds R4 closed, through themedium cf the normally closed connection established between posts I and 2 within a time relay relay TDR'Z, a commercial timer device of known form giving accurate and adjustable periods of delay in transmittingan electrical impulse; :post 2 of this relay is for this purpose connected by jumper with post 5 there'- of, which completes the circuit of -v'o1t current via lead M. The action described so far occurs instantly with no time delay. The same closing movement of the armature of R4 connects a branch'of wire8 with a lead 15 running thr'o'ugh post l5 on board -HJ-| to-solenoid 90 of shearing uni-tn, andalso connects the return lead 1'6 from the solenoid to a lead Q4 running to 'a normally open contact in a power relay R1. The circuit is thus pre-set to solenoid -99; The actuation of R! in due course *by the time delay relay TDRI causes one of the contract makers of R1 to connect lead 2 4 with branch 26 of wire 1 carrying the-available line voltage, such as 440 volts, thus energizing solenoid 90 of section A to lift the blades clear of the cloth and suspend the sh'e'a'ring. s i

The same movement of the "contact makers of R4 puts a branch of load l4 into connection with a lead -28 running to post 4 on a time 'rel'ay relay TDR'I identical in' construction 'with T13R17, thl'is in efiect connecting :posts l and "5 thereof together which in accordance with the manner of construction and operation of these timers some 'IDR'I to measure 'off the definite time delay foi' which it is set by ineans'df its potentioine't'e'r "k'nbb 2 9 -and accompanying scale. Both TDRI enn T-DRZ are supplied with lid-volt current by branches of leads and 23 from TI 'runnfiigto posts 5 and 6 respectively on the time delay 3%- lays. 'At the "expiration of this measured-interval of time, TDR'I acts to make internal contact between its posts 2 and 3, and thus to "the branch of lead 2'5, conriected to itspost 2, liito connection "with lead 133 attached to it's post 3,

thus s pplying ll'Of-i/ol-t current i rorh 1! he ieaa I4 and the normally eiosed'cdntact between posts I and '2 of TDR2, and the said branch or "wire 25, into the coil of R1, thus sending 440'-1volt current via leads v26, 24, through R4 and via leads I6, I5, and 8 intothe solenoid 90 to. lift the blades and suspend the shearing.

It is noted that when R1 is energized by the action of TDRI, a holding circuit is established between a branch of lead 25 and one end, I3, of the coil of R1, whereby TDR2holds R7 in action so long as TDR2 maintains its internal connec-v tion'between its posts I and 2, I

In each relay TDRI and TDRZ, the construction is such that posts I and 2 are normally con-' nected, and that connecting post 4 to causes this device to start measuring off its time and at the expiration'of the period of delay forwhich the device is set, to break this connection between posts I and 2 and establish a connection between posts 2 and 3 which remains solong as post 4 is kept connected to post 5; but when connection between posts I and 5 is broken, the connection between posts I and 2 is reestablished and that between 2 and 3 is interrupted. The action of RI in actuating R4 to cause the latter to make connection between posts t and 5 of TDRI and thus start the delay relay measuring off its time, and thereafter making contact between its posts 2 and 3 to actuate R'I has just been explained. The same momentary action of RI in response to feeler contact, however, has already broken an otherwise constant connection between posts 4 and 5 of TDR2, by opening a normally closed contact in RI between a branch of lead I4 to post 5 and a lead 30 running to post 4 of 'I'DR2. As the timing period of TDRZ is initiated by connecting points 4 to 5 thereof as seen, and as these points are normally kept connected by RI, TDR2 stands normall in its timed-out relation, i. e., at the end of its cycle, with internal connections broken between its posts I and 2. The opening of the contacts in RI between leads I4 and 30 thus re-sets TDR2 to start on another timing cycle, its points I and 2 being thus instantly connected to provide for the circuit which holds R4 energized to permit the other timer to time out and lift the blades to suspend the shearing, TDR2 itself thentiming' out a brief but accurately measured and adjustable fraction of a second later to open the contact between its posts I and 2 and thus drop out R4 and 13.1 with resultant de-energizing of solenoid 90 and allow the shearing blades to fall back and resume the shearing immediately after the seam has passed the shearing point.

If the approach of a crooked seam should cause a second or even more actuations of the feeler devices before this entire cycle of suspending and resuming the shearing shall have been com pleted, the resultant momentary interruption of contact between leads I l and in RI merely resets TDR2 back to the beginning of a fresh cycle, still without breaking the connection between its posts I and 2, thus extending the delay produced by this timer beyond its normal period, The action of TDRI is not changed by the second feeler impulse, but functions to cause the lifting of-the blades in time to clear the first end or portion of the seam, because its action is initiated by R4, which remains unaffected by a second or otherwise repeated action of RI during the cycle of TDRI. Thus, onl the moment of resumption of the shearing action is postponed and the length of the jump of the knives is extended toinclude the whole crooked seam, with resultantjavoidance of damage to the fabric or the blades through cutting the seam.

-As is'obvious, sinceTDRI and TDRZ start measuring off their intervals of time at the same instant, and the former-controls the instant of suspension of the shearing while the latter controls the instant of'resumption of shearing, the control knob 29 of TDRZ is set to produce a slightly longer delay than TDRl. That is, TDRI measuresofi accurately the length of time needed for the seam to travel from its location at the moment when its approach is detected by feeler 92, to a predetermined location as close to the shearing point as is deemed safe; while TDRZ, starting to run at the same instant as its companion device and by the same feeler impulse, is set town a fraction of a second longer than TDRI, this additional time measuring the duration and hence the length of the jump of the knives to clear the seam, these time settings being madeincdueaccord with the speed of travel of the cloth. By reason of the accuracy of the organization set forth herein, sure and safe clearance ofa trimmed and butted seam is attained even at cloth speeds up to 60 yards per minute with a total jump of only 2 inches, which means that only this 2-inch bandof unshorn length of cloth must be discarded from the finished fabric, with obvious saving over priorpractice.

When the seam arrives successively at the second and third shearing sections B and C of the multiple shear, substantially identical sequences of operations are initiated. Thus, when feeler wires 93 make contact with platen roll. 95 of section B, -12-volt current-from T2 momentarily energizes R2, similar to RI, this in turn energizing R5, corresponding to- R4 of sectionA of the shear, thus pre-setting the 440-volt circuit via leads I1 and 48130 solenoidSI, and also starting TDRI and TDRZ to measure off their respective times. When TDRI runs out its time, it actuates master relay R'I as before, thus closing the contact between leads 26 and 24 to put 440- volt current into solenoid 9| via leads I7 and I8. A fraction of a second later, TDR2 times out, opening the connection between its posts I and 2 and releasing relays R5 and R1 to permit the knives to resume shearing relation with the cloth.

In substantially identical manner, feeler I02 of section C of the cloth shear actuates R3 and R6 to cause TDRI and TDRZ to control the actuation of power relay R1 and thus the action of solenoid I03 to jump the blades of this section over the seam.

As noted, thesettings of TDRI and TDR2 must be made in proper accordance with the speed of travel of the cloth. Hence these settings must be accurately reset whenever the cloth speed is varied. Since occasions for varying the cloth speed arise frequently,"I have provided means, of which one form is shown in Figs. 3 to 5, for linking the controls of the time delay relays directly to the devices governing the rate of travel of the cloth through the shear, so that the relay controls will be automatically and mechanically shifted to match the speed of the cloth, without the need for independent manual setting of the periods of delay of the two relays, with resort to trial and error and the incidental trouble and times loss and possibility of injury to the cloth or to the knives thus involved. For this purpose, the panel I05 on which TDRI and TDR2 and the other relays and transformers are mounted, together with its cover I06, are fastened to the inside of one of the end frames I01 of the shear, adjacent the variable speed driving unit which provides the power propelling the cloth through the sheen. A short arm I09 is fixed on the control shaft of each time delay relay, and these two arms are, connected together by a link III the end of which is attached by a second link II3 to a bolt H5 eccentrically diss posed in a hub III fixed on one endv Of a rock. shaft II9 ina bearing I2I on frame III]. The other end of the rockshaft has fixed thereon arm I23 connected by link I25 to the upturned end of an arm I21 rigidly fixed on the base .or slide I29 carrying the motor I3I and variable diameter pulley I33 of the variable speed drive. By this arrangement, when the motor 131 is shiftedoncits base I35 by rotation of hand-wheel I31 and the adjusting screw connected therewith to move it toward the driven pulley 138, so that the tension of V-loelt :Ifilflis slackened and pulley I33 expands to increase thespeed imparted to driven pulley I38, the control shafts of "IDR-I and TDR2 are rotated counter-clockwise to cut down the time delay exact accord with the increase in the speed of travel of the cloth produced by the usual connections (not shown) "between the shaft of pulley I38 and the feed-rolls of the shear. .A corresponding increase in the zdelay'produced by each unit is effected when the motor MI is moved 'reverse'ly on its base to stow down the speed :of cloth travel.

The setting and adjustment of the extent of rotation :of the control shafts of the two time delay relays by :the linkage so that the suspension will always occur just as the seam arrives within :an inch .or two of each successive shearing point, regardless of changes in cloth speed, is effected by mounting the eccentric bolt I I5 for adjustment radially in a slot I I8 extending diametrically across the end of hub III, This adjustment is ordinarily needed and effected only in. setting up the machine, and once found the compensation :for changes in cloth speed is made automatically by .the .act of moving the control governin the cloth speed. As is obvious, the nearer the :bolt I:It5 is .set :to the axis of the hub ii], the less will .be the throw of the control shafts of the relays for a given degree of shift of motor I3I and of change in the rate of travel of the cloth. 1'10 vary the length of jump, :the angular thmw'of the control shaft of TDRZ "that is-ivtthi-n the hub of its arm 109 is increased slightly over that given the control shaft 'of TDRII, ashy shifting slightly in a :radialdirection the operative position of the pivot connectingarm tl'ili of "IDRZ its'link I I I toshorten the effective length of such arm. This causes theduration :of the suspension of shearing to varied automatically in 'proportion to the changes in cloth speed, so that the length of unshorn f-albric adiiaeoritthe seams that is jumped. -by the shearing knives remains constant regardless of the cloth speed.

In lieu of this mechanical linkage to the controls of both timers, means is sometimes-provided for increasin or shortening the'timing pe riods of both timers, by varying the electrical circuits within thetwo timers simultaneous'lmthe setting of a potentiometer or'othercontrol device common to both timers being for this purpose var'iedjn proportiontothe movement of the controls governingthe cloth speed.

While I have-illustrated and described certain forms in which the'inventionmaybe embodied, I ,am aware that many modifications "may be made therein by any I person skilled in the ,art,

withoutdepartlng from the scope of the inventticn as expressed in the claims, Therefore, I do not wish to be limited to the particular forms shown, or to the details of construction thereof, but what i do claim is:

'1. In a cloth shear, in combination, means propolling, uiding, and shearing the cloth, means suspending the shearing to pass a seam in the cloth, detector devices detecting the approach of a seam to the shearing point, means receiving and holding an impulse from the detector devices until the seam arrives in proximity to the shearing point, and thereupon transmitting such impulse to the shearing-suspending means .to stop the shearing while the seam passes the shearing point, and addtional means adjustable to suit the cloths speed effecting a resumption of the shearing operation after the seam has passed a predetermined distance beyond the shearmg point. r

2. In a cloth shear, in combination, means propelling, guiding, and shearing the cloth, means detecting the approach of a seam to the shearing point, means actuated by such detecting means suspending the shearing to pass the seam, and means variably predetermining hoth the delaybetween such detection and the suspension of the shearing, and also the duration of the sus-' pension.

3. In a cloth shear, in combination, means propelling, guiding, and shearing the cloth, means detecting the approach of a seam portion to the shearing point, means actuated by such detecting means suspending the shearing to pass the seam, timer means adjustably predetermining a constant time delay between detection and suspension, and timer means set in action :by the detecting means and adjustable to effect a predetermined minimum duration of the suspension of shearing and automatically extending the duration of suspension if a second seam portion is detected after detection of the first seam poritionbut=before resumption of shearing.

4. In acloth shear, in combination, means propolling, guiding, and shearing thecloth, means detecting the approach .of a seam .to the shear.- ing point, means actuated by such detecting means suspendin the shearing to pass the seam, a timer set inaction by the detecting means and intervening between such means and the sheartrig-suspending means to delay the action of the latter, and a second timer also set in action :by the detecting imeansterminating {the action of the shearing-suspending means.

*5. Ina-cloth shear, incombination, means .propolling, guiding, and shearing the cloth, means detecting the approach of a seam to the shearpoint, means suspend-ing the shearing to'pass the seam, and two timers put in action -by :the

, detecting means, one thereof actuating :the

Shearing-suspending means after a delay, and the other effecting resumption of the shearing after a further delay. ii. *In a cloth shear, in combination, means -propolling, guiding, and shearing the cloth, means detecting the approach of -a-seam to the shearing point, means-suspending-the shearing to pass the seam'and two timers put in action substantia'lly at the same time by the detecting means, one *thereof actuating =the shearing-suspending means after a delay, and the other effecting ryesumption of shearing after afurtherdela y.

"7. Jnaplothshefl,'in'eombination means pmpolling, guiding, and-shearing the "cloth-means detecting the approach of a seam to the shearing point and completing an electrical circuit upon suchdetection, electro-magnetic means suspending'the shearing, a time delay relay set in actionQby completion of such circuit, to energize the electro-magnetic means after delay, and a second time delay relay acting to de-energize the electro-magnetic means.

8. In a. cloth shear, in combination, means propelling, guiding, and shearing the cloth, means detecting the approach of a seam to the shearing point and completing an electrical circuit upon such detection, electro-magnetic means suspending the shearing, a time delay relay set in action by completion of such circuit and acting to energize the electro-magnetic means after delay, and a second time delay relay acting to de-energize the electro-magnetic means after lapse of a predetermined minimum time following the completion of the circuit by the detecting means.

9. In a cloth shear, in combination, means propelling, guiding, and shearing the cloth, means detecting the approach of 'a seam to the shearing point and completing an electrical circuit upon such detection, electro-magnetic means suspending the shearing, a time delay relay set in action by completion of such circuit and acting to energize the electro-magnetic means after delay, a second time delay relay acting to de-energize the electro-magnetic means after lapse of a predetermined minimum time following the completion of the circuit by the detecting means, and means adjusting the respective periods of delay.

10. In a cloth shear, in combination, means propelling and guiding the cloth, shearing means shearing the cloth at a plurality of points in its passage through the shear, means associated with each shearing means to detect the approach of a seam in the cloth, means associated with each of the shearing means suspending the shearing action, and timing means common to all the shearing-suspending means actuating the latter successively to suspend the shearing as the seam reaches each shearing point in turn.

11. In a cloth shear, in combination, means propelling, guiding, and shearing the cloth, means detecting the approach of a seam in the cloth to the shearing point and closing an electric circuit upon such detection, means suspending the shearin to pass a seam, a power relay actuating the shearing-suspending means when energized, and time delay relays set in action by the closing of the said circuit and respectively energizing and tie-energizing the master relay after delay.

12. In a cloth shear, in combination, means.

propelling, guiding, and shearing the cloth, means detecting the approach of a seam in the cloth to the shearing point and closing an electric circuit upon such detection, means suspending the shearing to pass a seam, a relay actuated upon closing such circuit, a holding relay actuated by the first relay, time delay relays set in action by the said relays, and a power relay energized by one of the time delay relays after delay and de-energized by the other time delay relay after further delay.

13. In a multiple cloth shear, in combination, means propelling and guidin the cloth, a plurality of shearing units shearing the cloth at spaced points in the length thereof, each having electrically-operated means suspending its shearing action and also devices detecting the approach of a, seam to the shearing point, separate relay means for each unit including circuit-holding devices each actuated by its associated detecting device, and a power relay transmitting power successively to the several shearing-sus pending means as the separate relay means are actuated; v

14. In a multiple cloth shear, in combination, meanspropelling and guidin the cloth, a plurality of shearing units'each having means to detect the approach of a seam and means suspending its shearing action, power means common to all units for actuating the shearing-suspending means, and timing devices common to all units co-ordinating the actuation of each shearing-suspending means with the arrival of the seam at the shearing pointof such unit.

15. In a multiple cloth shear, in combination, means propelling and guiding the cloth, a common power means, a plurality of shearing units each havin means to detect the approach of a seam and also electro-magnetic means suspending its shearing action which latter means is put in communication with the power means by the seam-detecting means, and time delay devices controlling the common power means and variably predetermining the moment and duration of its actuation to energize the electro-magnetic means.

16. In a multiple cloth shear, in combination, means propelling and guiding the cloth, a source of electric power, a plurality of shearing units each having a seam-detector and electro-magnetic seam-passing devices, a switch connected to the power source selectively put in connection r with the electro-magnetic seam-passing devices of a unit by the action of the seam-detector of such unit, and time delay devices closing the switch after a predetermined period of delay and re-openin it after a further predetermined minimum period of delay.

17, In a multiple cloth shear, in combination, means propelling and guiding the cloth, a plurality of shearing units each having a seamdetector and electro-magnetic shearing-suspending means, a plurality of relays each connected to one of the seam-detectors, a plurality of holding relays each actuated by a particular one of the first relays, a power relay providing actuating power for the electro-magnetic shearingsuspending means of all the shearing units, and selectively put in connection with the shearingsuspending means of a given unit by the holding relay of such unit, a time delay relay set in action by each of the seam-detectors in turn and acting after a predetermined and adjustable delay to actuate the power relay to suspend the shearing of the shearing unit associated with the particular seam-detector actuating the time delay relay, and a second time delay relay set in action by the same seam-detector at substantially the same time and de-energizing the power relay to cause resumption of shearing by this unit after delay.

18. In a cloth shear, in combination, shearing means. seam-detecting and shearing-suspending means, means propelling the cloth at variable speeds, timing devices powered independently of the cloth-propelling means producing delay between the action of the seam-detecting means and the actuation of the shearing-suspending devices, and means connecting the propelling meansand the timing devices causing automatic variation of the length of the delay in response to variation in the speed at which the cloth is propelled,

propelling, guiding, and shearing the cloth, means detecting the approach of a seam to the shearing point, means powered independently of the cloth-propelling means set in action by the detecting means and suspending the shearing for a predetermined minimum interval of time, and means connected with the propelling means automatically varying the duration of such suspension of shearing in accordance with variation in 10 the speed of travel of the cloth.

WILFRED N. HADLEY. v 

